Spring testing machine



AFgf 7, 1945- G. G gyrll coxl SPRING TESTING MACHINE Filed May 24, 1944 2 Sheets-Sheet l Aug. 7, 1945. G. G. wlLcox I 2,381,241

SPRING TESTING MACHINE Filed May 24, 1944 2 Sheng-sheet 2 This invention relatesto devices for testing the fatigue life of compression springs, bywhich is meant the number of times the springl may be compressed without failure. f

. It is the principal object of the inventionl toV vide a spring testingmachine of the described y ytype which is so constructed and operative that only a part ofthe pluralityofsprings being tested at any timev constitute a load on the machine, kwhile the others actually return work to the machine and thereby reduce the power 'requirement. 1

. Other objects and features of novelty of the' invention will be made apparent by the following description and the annexed drawings which, it will be understoodare only Villustrative of the invention and impose no limitation .thereon not imposed by the appended claims.

Referring to the drawings in which similary reference numerals refer to like parts,

Fig. 1 is an velevational View of a'spring testing machine according to the invention;

Fig. 2 lis a sectional viewtaken on line 2--2 of Fig. 1.

Themachine illustrated in the drawings and which is constructed in accordance with my invention comprises a circular backing plate 2 havin'ga peripheral ange 4 extending at right angles therefrom. An annular lridge Bof substantial radial width is integrally connected to the backingplate 2 and extends therefrom in the same direction as the ange 4 and to .approximately the same extent, thus forming an annular space 8 between the ange 4 andthe ridge 6 and a ciri cular space (ID at the 'center of the structure and s within the annular ridge. l I `Means are provided by the invention for supporting the springs undery test vwithin the annular space v8 andcomprise means for rigidly but adjustably supportingthe outerfendzof each spring `A and means forreciprocably'supporting the inner end thereof whereby each spring is alteri nately compressed and released as the machine is operated. The means for' supportingl the lar space 8. Handle means 24 may be .provided on the outer end of each bolt and clamprneans 55 tch., Co'nn a` 26 may beiassociatedfwitheactr bolt externally of iiange 4in order to hold the bolts in any desired position. In the disclosed embodiment twelve bolts and abutments are shown, being equally spaced about the annular iiange 4.

The means for reciprocably supporting the f inner ends of the springs under test comprise a plurality of radially-extending rods 30 which are slidably received in' radial openings 32 in the annular ridge 6 and each of which is radially aligned with one of the bolts 20. The rods -30 are of such length that the outer end of eachis positioned within the annular space 8 and the inner end is positioned within the central space I El. At its outer end each rod carries an abutment member 34 which is opposite and in radial alignment with the abutment 22 on the aligned bolt 20 and is adapted to cooperate with abutment 22 to hold the opposite ends of a helical coil compressionv spring.

Means are provided by the invention for reciprocating the rods 3U to thereby alternately compress and release the springs held between the abutments.v Such means comprise a motor having a shaft 42 which extends axially into the central opening I0 and, within such opening, is connected eccentrically to a circular disk 44 which is surrounded by a ring 46 and separated therefrom by frictionless bearings 48. The inner ends of the rods 30 bear on'the annular outer periphery of the ring 46 and are reciprocated Aradially of the structure by rotation of the shaft abutments, 22, 34 at the center of the upper part of Fig. 1. The cam 44 is first rotated until the part of its exterior surface adjacent these abutments is a maximum distance therefrom, i. e. in the position shown in Fig.. 1. A spring -is now placed between these'abutments and the bolt handle 24 operated to screw the abutment 22 linwardly until a predetermined load ,is placed on r the spring, which will be theminimum load thereon during operation of the machine. The cam isthen moved successively through 30 increments in order to position each spring in the described manner. Operation of the driving motor will rotate the eccentric 44 thus causing the ring 46 to progressively compress the springs.

As some of the springs are expanding and returning work to the system at the same time that others are being compressed the net work done by the driving system is reduced to a minimum.

While I have described and illustrated one embodiment of my invention it will be apparent to those skilled in the art that other embodiments, as well as modifications of that disclosed, may be made and practiced Without departing in any i way from the spirit or scope of the invention, for

the limits of which reference must be had to the appended claims.

1. A'machine'for testing helical coil compression lsprings comprising a rotatable shaft, a cilcular disc connected ecoentrically to said shaft,

a ring surrounding the disc and supported there'y on by frictionless bearings, an annularseriesof devices surrounding said ringV and having parts slidably engaging the periphery thereof andeach being adapted to support the inner end of one of an annular 'series of radiallypositioned helical coil springs, and means for rigidly supporting the outer end of each of said springs whereby rotation of the shaft will cause said springs to be 20 alternately compressed and released.

able shaft at the center of said annular series, a circular disk connected eccentrically to said shaft, a ring surrounding said disk and supported thereon byv frictionless bearings, and a plurality of connecting' rods which slidably engage the periphery of said' ring at their one ends and at their' other ends'are respectively connected to the devices of said second annular series.

GEORGE G. WILCOX. 

